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                                                                        Linux保护技术
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        2021-02-02
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                                                                        <span class="post-pubtime"> 本文共390字 </span>

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        大约需要1min
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            <b>#</b> PWN
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                                                                        <p>[TOC]</p>
<h1 id="linux保护技术"><a href="#linux保护技术" class="headerlink" title="linux保护技术"></a>linux保护技术</h1><h2 id="NX保护"><a href="#NX保护" class="headerlink" title="NX保护"></a>NX保护</h2><h3 id="作用："><a href="#作用：" class="headerlink" title="作用："></a>作用：</h3><p>​	将数据（栈，堆）所在内存页标识为不可执行，当程序成功转入shellcode时，程序会尝试在数据页面上执行指令，此时CPU就会抛出异常，而不是去执行恶意指令</p>
<h3 id="编译选项："><a href="#编译选项：" class="headerlink" title="编译选项："></a>编译选项：</h3><ul>
<li>关闭：</li>
</ul>
<blockquote>
<p>-z execstack</p>
</blockquote>
<ul>
<li>开启：</li>
</ul>
<blockquote>
<p>-z noexecstack</p>
</blockquote>
<h2 id="PIE保护"><a href="#PIE保护" class="headerlink" title="PIE保护"></a>PIE保护</h2><h3 id="作用：-1"><a href="#作用：-1" class="headerlink" title="作用："></a>作用：</h3><p>​	使得程序地址空间分布随机化，增加ROP等利用的难度</p>
<h3 id="编译选项：-1"><a href="#编译选项：-1" class="headerlink" title="编译选项："></a>编译选项：</h3><ul>
<li>​	关闭：</li>
</ul>
<blockquote>
<p>-no-pie</p>
</blockquote>
<ul>
<li>​	开启：</li>
</ul>
<blockquote>
<p>-pie -fPIC</p>
</blockquote>
<h2 id="canary保护"><a href="#canary保护" class="headerlink" title="canary保护"></a>canary保护</h2><h3 id="作用：-2"><a href="#作用：-2" class="headerlink" title="作用："></a>作用：</h3><p>​	函数开始执行的时候会先往栈里插入canary值，当函数真正返回的时候会验证canary值是否合法，如果不合法就停止程序运行。可以防止栈溢出覆盖返回地址</p>
<h3 id="编译选项：-2"><a href="#编译选项：-2" class="headerlink" title="编译选项："></a>编译选项：</h3><ul>
<li>关闭：</li>
</ul>
<blockquote>
<p>-fno-stack-protector</p>
</blockquote>
<ul>
<li>启用（只为局部变量中含有char的函数插入保护代码）：</li>
</ul>
<blockquote>
<p>-fstack-protector、</p>
</blockquote>
<ul>
<li>启用（为所有函数插入保护代码）：</li>
</ul>
<blockquote>
<p>-fstack-proctor-all</p>
</blockquote>
<h2 id="Fortify保护"><a href="#Fortify保护" class="headerlink" title="Fortify保护"></a>Fortify保护</h2><h3 id="作用：-3"><a href="#作用：-3" class="headerlink" title="作用："></a>作用：</h3><p>主要用来防止格式化字符串漏洞。包含%n的格式化字符串不能位于程序内存中的可写地址。当使用位置参数时，必须使用范围内的所有参数，如果要使用%7$x，必须同时使用1$2$3$4$5$6$。</p>
<h3 id="编译选项：-3"><a href="#编译选项：-3" class="headerlink" title="编译选项："></a>编译选项：</h3><ul>
<li>关闭：</li>
</ul>
<blockquote>
<p>-D_FORTIFY_SOURCE&#x3D;0</p>
</blockquote>
<ul>
<li>开启：</li>
</ul>
<blockquote>
<p>-D_FORTIFY_SOURCE&#x3D;2</p>
</blockquote>
<h2 id="RELRO保护"><a href="#RELRO保护" class="headerlink" title="RELRO保护"></a>RELRO保护</h2><h3 id="作用：-4"><a href="#作用：-4" class="headerlink" title="作用："></a>作用：</h3><p>设置符号重定位表为只读，并在程序启动时就解析并绑定所有动态符号，从而对GOT表攻击。</p>
<h3 id="编译选项：-4"><a href="#编译选项：-4" class="headerlink" title="编译选项："></a>编译选项：</h3><ul>
<li>开启（部分）：</li>
</ul>
<blockquote>
<p>-z lazy</p>
</blockquote>
<ul>
<li>开启（全部）：</li>
</ul>
<blockquote>
<p>-z now</p>
</blockquote>

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        <ol class="toc"><li class="toc-item toc-level-1"><a class="toc-link" href="#linux%E4%BF%9D%E6%8A%A4%E6%8A%80%E6%9C%AF"><span class="toc-text">linux保护技术</span></a><ol class="toc-child"><li class="toc-item toc-level-2"><a class="toc-link" href="#NX%E4%BF%9D%E6%8A%A4"><span class="toc-text">NX保护</span></a><ol class="toc-child"><li class="toc-item toc-level-3"><a class="toc-link" href="#%E4%BD%9C%E7%94%A8%EF%BC%9A"><span class="toc-text">作用：</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#%E7%BC%96%E8%AF%91%E9%80%89%E9%A1%B9%EF%BC%9A"><span class="toc-text">编译选项：</span></a></li></ol></li><li class="toc-item toc-level-2"><a class="toc-link" href="#PIE%E4%BF%9D%E6%8A%A4"><span class="toc-text">PIE保护</span></a><ol class="toc-child"><li class="toc-item toc-level-3"><a class="toc-link" href="#%E4%BD%9C%E7%94%A8%EF%BC%9A-1"><span class="toc-text">作用：</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#%E7%BC%96%E8%AF%91%E9%80%89%E9%A1%B9%EF%BC%9A-1"><span class="toc-text">编译选项：</span></a></li></ol></li><li class="toc-item toc-level-2"><a class="toc-link" href="#canary%E4%BF%9D%E6%8A%A4"><span class="toc-text">canary保护</span></a><ol class="toc-child"><li class="toc-item toc-level-3"><a class="toc-link" href="#%E4%BD%9C%E7%94%A8%EF%BC%9A-2"><span class="toc-text">作用：</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#%E7%BC%96%E8%AF%91%E9%80%89%E9%A1%B9%EF%BC%9A-2"><span class="toc-text">编译选项：</span></a></li></ol></li><li class="toc-item toc-level-2"><a class="toc-link" href="#Fortify%E4%BF%9D%E6%8A%A4"><span class="toc-text">Fortify保护</span></a><ol class="toc-child"><li class="toc-item toc-level-3"><a class="toc-link" href="#%E4%BD%9C%E7%94%A8%EF%BC%9A-3"><span class="toc-text">作用：</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#%E7%BC%96%E8%AF%91%E9%80%89%E9%A1%B9%EF%BC%9A-3"><span class="toc-text">编译选项：</span></a></li></ol></li><li class="toc-item toc-level-2"><a class="toc-link" href="#RELRO%E4%BF%9D%E6%8A%A4"><span class="toc-text">RELRO保护</span></a><ol class="toc-child"><li class="toc-item toc-level-3"><a class="toc-link" href="#%E4%BD%9C%E7%94%A8%EF%BC%9A-4"><span class="toc-text">作用：</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#%E7%BC%96%E8%AF%91%E9%80%89%E9%A1%B9%EF%BC%9A-4"><span class="toc-text">编译选项：</span></a></li></ol></li></ol></li></ol>
      
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